1. Field of the Invention
The present invention relates to an optical recording and reproducing apparatus and a tilt adjusting method, and more particularly, to an optical recording and reproducing apparatus for adjusting a tilt of an optical pickup in accordance with the amount of jitter of a reproducing signal, a tilt adjusting method therefor, and a recording control method therefor.
2. Description of the Related Art
An optical pickup of an optical recording and reproducing apparatus requires an actuator which is an object lens driver. The actuator may precisely move the object lens to a desired position in response to a magnetic field generated by a permanent magnet.
However, when an optical disk is curved while the optical recording and reproducing apparatus records and reads information on or from the disk, or when there is a tilt in an optical pickup during assembly of the optical recording and reproducing apparatus, the optical signal deteriorates. In order to compensate for the deterioration of the optical signal, the relative tilt amount between the disk and the object lens must be measured to remove the measured tilt amount.
FIG. 1 shows the structure of a conventional tilt adjusting apparatus. The apparatus of FIG. 1 includes a tilt detector for applying an optical signal to the disk and detecting the tilt amount by the optical signal reflected from the disk and a tilt motor (not shown) which adjusts the tilt of the optical pickup in accordance with the detected tilt amount.
The tilt detector includes a light emitting device 12 fixed on the optical pickup 10 and light receiving devices 14a and 14b to detect the tilt amount between the optical axis and the disk. The signals detected from the light receiving devices 14a and 14b become input signals for driving a tilt motor through a differential amplifier (not shown).
The tilt motor drives the optical pickup 10 to remove the tilt amount and thus to suppress deterioration of the optical signal. The optical pickup 10 pivots around a fixing and supporting axis 18. The tilt motor moves one side of the optical pickup 10 upward or downward around the fixing and supporting axis 18.
However, in the conventional tilt adjusting apparatus of FIG. 1, the tilt detector is arranged on the upper surface of the optical pickup to apply an optical signal to the disk or the size is relatively large, which defined a space.
The tilt detector cannot be arranged in the same position as the objective lens, so that the tilt amount of a current reproduction position cannot be precisely detected.
An additional adjusting apparatus is required to obtain an initial position when the tilt detector is installed on the upper surface of the optical pickup. Also, the amount of light is changed according to the reflection rate of a disk when light beams emitted from the light emitting device are reflected from the disk, so that the precision of tilt measurement and tilt adjustment is deteriorated in a disk having a low reflection rate.